The present invention relates to the field of fingerprint recognition. More particularly, the invention relates to an expansion card with an integrated fingerprint acquisition device on a retractable access portion of the card.
Computer security and access is an important issue. Methods of identifying individuals are important to providing computer access only to predetermined users. Fingerprints provide a unique and absolute means of identification that does not require remembering passwords and is also difficult to falsify.
Electronic fingerprint acquisition systems have been introduced to eliminate the need for ink or a chemical reagent. In such systems, the subject""s fingertip is pressed against or rolled over a flat transparent (e.g. glass) platen in an optical system. Light is directed through the platen and is reflected from the fingertip into an optical path including mirrors, lens and an electronic image sensor such as a CCD imager of the type employed in video cameras. The image of the fingerprint may be digitized, analyzed, printed out, stored, transmitted or compared with an existing fingerprint or fingerprints. See, for example, U.S. Pat. No. 5,732,148, incorporated herein by reference.
A problem with existing electronic fingerprint acquisition systems is that they tend to be bulky and large in size. While the general size of fingerprint acquisition systems has been reduced in recent years, the size is generally prohibitive for efficient use with laptop computers, notebook computers, or other devices with expansion slots, hereinafter referred to collectively as portable computers.
Portable computers are more limited in space than are desktop computers. The internal spatial restrictions of portable computers have required the establishment of standards for the internal accessories of these computers. One set of standards applicable to PC Cards, also referred to as PCMCIA cards, was developed by the Personal Computer Memory Card International Association (PCMCIA). The PCMCIA promulgated standards for PC Cards that are now virtually universal in the portable computer industry. The PCMCIA promulgated standards stating that the spatial standards for all PC Cards used in portable computers should be restricted to a rectangular space approximately 54 mm in width and 85.6 mm in length. Additionally, Type I, Type II, and Type III cards would have a thickness of 3.3 mm, 5 mm, and 10.5 mm, respectively.
In keeping with the PCMCIA standards for memory cards, internal modem manufacturers have adopted the same spatial standards for use with their portable computer communications cards. By complying with the standards established by the PCMCIA for memory cards, communications card manufacturers assured themselves compatibility and spatial conformity with computers utilizing the PCMCIA standards.
With most, if not all, new portable computers being manufactured with at least one PCMCIA peripheral slot, the PCMCIA specifications are now regarded as a standard in the portable computer industry for internal accessories.
There exists a need for a fingerprint acquisition device which is capable of being used in conjunction with a portable computer without additional space requirements. The prior art, as shown in FIG. 1, shows electronic fingerprint acquisition systems that attach to a desktop or portable computer via the serial port, the parallel port, or a Universal Serial Bus (USB) port. These devices tend to be bulky, reside outside of the computer""s housing, and require a lengthy cord. Further, when these devices are not in use, the device is still taking up often limited space surrounding the portable computer. An example of such a device is the U.are.U Fingerprint Recognition System available from Digital Persona, Inc. in Redwood City, Calif.
Users of portable computers often desire as few external peripheral attachments as possible. External peripheral attachments take up extra baggage space, are more easily broken and lost, and require additional functional space when in use. People often use portable computers in confined spaces, such as while seated in an airplane, that are not conducive to the extra space required by external peripheral devices attached to a portable computer. This is one reason for the development of standards, such as PCMCIA, for internal accessories of portable computers.
The first PCMCIA cards developed for communication accessories generally required an intermediate cable extending from the PCMCIA card. An example is provided with respect to modems. The intermediate cable is adapted to connect between the PCMCIA card and a standard telephone RJ-11 cable. A problem with this configuration is that if the cable is damaged or lost, the accessory is unusable until the cable is repaired or replaced. One solution to this problem is to have a cable jack that is extendable from the PCMCLA card, as described in U.S. Pat. Nos. 5,336,099 and 5,338,210.
The present invention relates to a fingerprint acquisition system. More particularly, the invention relates to an expansion card with an integrated fingerprint acquisition device on a retractable access portion of the interface card. The invention provides an extension to the interface card that protrudes from the laptop computer providing a permanent interface. That is, the portion of the interface card protruding from the computer provides the scanning area on which a fingerprint is received. This structure eliminates the need for an intermediate cable. The extension is retractable into the interface card when not in use, thereby preventing the fingerprint reader from damage.
In an exemplary embodiment, the expansion card is constructed such that a retractable access portion, or carriage, is able to slidably extend out from the end of the expansion card. Constructed to fit on the carriage, the fingerprint acquisition device has the capability of extending from and retracting back into the expansion card housing. Thus, the fingerprint acquisition system is only exposed outside a portable computer when it is necessary to scan a fingerprint. While not in the use, the fingerprint acquisition device is retracted into the expansion card, providing added protection for the fingerprint acquisition device from damage, and leaving more usable space surrounding the portable computer. When the fingerprint reader is extended outside the protective casing and exposed to human finger touch, it may, over time, accumulate oil or foreign particles on its surface. Addressing this concern, the invention cleans the prism surface as the reader is extended out from and retracted into the expansion card.
In one embodiment, the expansion card is constructed in accordance with CMCIA standards, and the fingerprint acquisition device includes an imaging prism, a focal lens, a redirectional prism, an image sensing means, and a diffused light source. The fingerprint image prism is optically coupled to the focal lens, which is optically coupled to a redirectional prism. The redirectional prism is further optically coupled to the image sensor.
An advantage of the invention is that the fingerprint recognition device is small enough to fit within a PCMCIA standard expansion card.
Another advantage of the invention is that the fingerprint recognition system, when not in use, is enclosed within a portable computer""s housing such that the invention does not use additional desk space in addition to the portable computer itself, other than that necessary for the retractable access portion to extend into an extended position.